Natural numbers enumerator on Ruby 2.0 using lazy evaluation

lazy.rb

natural_numbers = Enumerator.new do |yielder|
  number = 1
  loop do
    yielder.yield number
    number += 1
  end
end

p natural_numbers.lazy.select { |n| n.odd? }.take(5).to_a # => [1, 3, 5, 7, 9]
p natural_numbers.lazy.map    { |n| n*2    }.take(5).to_a # => [2, 4, 6, 8, 10]
p natural_numbers.lazy.select { |n| n.odd? }.map { |n| n*2 }.take(5).to_a # => [2, 6, 10, 14, 18]
p natural_numbers.lazy.select { |n| n.odd? }.select { |n| n<10 }.take(5).to_a # => [1, 3, 5, 7, 9]
p natural_numbers.lazy.map    { |n| n*3    }.select { |n| n.odd? }.take(5).to_a # => [3, 9, 15, 21, 27]